Swenson Wet Prairie

State Natural Area (No. 64)

Location: Within Avon Bottoms Wildlife Area, Rock County. T1N-R10E, Section 18 NW1/4. 40 acres.

Access: From the intersection of State Highway 11 and County Highway T in Brodhead, go south on T 5 miles, then east on Smith Road 0.25-mile to a parking area south of the road. Walk south on the access lane 0.25-mile to the northwest corner of the site.

Description: Swenson Wet Prairie lies in the low, flat floodplain of the Sugar River near its confluence with Taylor Creek. The site contains an excellent example of a wet-mesic prairie and sedge meadow with low river bottom savanna and scrub interspersed with shallow, abandoned river channels. The meadow is dominated by blue-joint grass, big and little blue-stem, Indian grass, and sedges. Numerous forbs include swamp milkweed, white wild indigo, shooting-star, blue flag iris, pale-spike lobelia, cardinal flower, prairie blazing-star, cup plant, Culver's-root, golden alexanders and Michigan lily. Two state- threatened plants, prairie Indian plantain (Arnoglossum plantagineum) and round-fruited St. John's wort (Hypericum sphaerocarpum), occur here. The savanna was perpetuated through a long history of grazing and is now overgrown by shrubs and other woody species. Some sloughs and low areas have standing water in all but the driest years. Summer resident birds include two state-threatened species, cerulean warbler (Dendroica cerulea) and Bell's vireo (Vireo bellii), along with the rare yellow-breasted chat (Icteria virens). Swenson Wet Prairie is owned by the DNR and was designated a State Natural Area in 1968.